3.2 Chromosomes

Which of the following accurately describes the structure of chromosomes?

A. Loosely coiled DNA and proteins

B. Tightly coiled RNA and lipids

C. Tightly coiled DNA and proteins

D. Loosely coiled RNA and lipids

What is the primary application of karyotyping?

A. Diagnosing bacterial infections

B. Prenatal screening for genetic disorders

C. Identifying viral genomes

D. Studying protein structures

How is sex determined in humans?

A. By the number of mitochondria

B. By the presence of X and Y chromosomes

C. By the type of ribosomes

D. By the number of lysosomes

Which genetic disorder is associated with the presence of an extra chromosome 21?

A. Turner syndrome

B. Klinefelter syndrome

C. Down's syndrome

D. Cystic fibrosis

What is the role of chromosomes during cell division?

A. Synthesizing lipids

B. Ensuring accurate DNA replication and distribution to daughter cells

C. Producing energy

D. Transporting proteins

a) Discuss the structure of chromosomes, explaining how they are composed of tightly coiled DNA and proteins. [3]

b) Elaborate on the role of chromosomes in cell division and inheritance. [2]

a) Explain the process of karyotyping and its significance in prenatal screening. [3]

b) Discuss how karyotyping can be used to diagnose genetic disorders, providing an example such as Down's syndrome. [2]

a) Discuss the process of sex determination in humans and the role of the X and Y chromosomes. [3]

b) Provide an example of a genetic disorder related to sex chromosomes and discuss its characteristics. [2]

a) Describe the molecular nature of genes and how they carry the genetic code in the form of codons. [3]

b) Explain how genes control the production of proteins. [3]

c) Discuss the significance of this control in the functioning of an organism. [2]

a) Define alleles and explain how they are different versions of the same gene. [3]

b) Differentiate between dominant and recessive alleles. [2]

c) Discuss the role of alleles in creating genetic diversity within a population. [3]